crab out of its shell

Question
hey there,
our largest crab was acting strangely, and one of the smaller crabs was on
top of it so i thought it might be ready to molt.  i separated it and it didn't do
much for a day or two.  then, it started climbing around being active, so i
thought maybe it wasn't going to molt.  well, then my son told me it had been
still for another day, so i decided to wait to put it back into the tank.  when i
just checked on it, it was completely out of its shell, not moving.  it never
molted.  i rinsed the crab & its shell and put them together in a glass cup, so
it would be near its shell, but it doesn't appear to be moving.  it doesn't stink
(yet) so i'm not sure if its alive.  my biggest concern is what happened.  i
sprayed it again to keep it moist and am keeping it in the dark.  any ideas?  
thanks for your time.
sue

Answer
There might be something in the shell preventing him from returning to it. Can you add a few more shells for him to choose from?

Misting him may be causing him stress right now, so for the time being I'd suggest not spraying him. Keep a tiny amount of water in the cup, not much, just enough so his abdomen doesn't dry out. Make sure that the temperatur and humidity are in the correct range.